EvilHomerThey could have at least made an effort to get the characters right! This doesn't feel like Luna and Celestia playing Portal. This feels like two guys playing Portal, and then someone draws in Luna and Celestia.

Crunchy FrogThat's exactly what it is. They took the audio from the series "Two Best Friends Play" and added ponies to the video. I also agree that Luna and Celestia were poor choices -- there is a popular fanon interpretation of Luna as a serious gaming nerd.

Rainbow Dash would indeed be a perfect stand-in for Celestia here. As for the other, I think a more established canon character would be more appropriate than Derpy. Spike, for example. Everyone likes to pick on Spike.

MurgatroidMendelbaumThey probably also should've gotten the original voice actors. And then instead of video games, they could be planting an orchard. And then instead of animated ponies, they could be fat brony aspies.